Transcript Interaction Design Chapter 7

HTTP://WWW.BADDESIGNS.COM/
Innovative Interface Design
IDENTIFYING NEEDS AND
ESTABLISHING
REQUIREMENTS
REVIEW
User Experience Goals
 Usability Goals
 Consistancy

 Internal
 External
Feedback
 Constraints
 Affordances

OVERVIEW
• The importance of requirements
• Different types of requirements
• Data gathering for requirements
• Task descriptions: Scenarios
Use Cases
Essential use cases
• Task analysis:
HTA
Requirements definition:
the stage where failure occurs most commonly
ESTABLISHING REQUIREMENTS
• Remember your thoughts evaluating the elevator
• Some thought to requirements, but probably
o informal
o unstructured
DIFFERENT KINDS OF REQUIREMENTS
• Functional:
What the system should do
Historically, the main focus of requirements activities
vs. Non-functional: memory size, response time...
• Data:
What kinds of data need to be stored?
How will they be stored (e.g. database)?
DIFFERENT KINDS OF REQUIREMENTS
Environment or context of use:
• physical:
• dusty? noisy? vibration?
• light? heat? humidity? ….
• (e.g. insects, ATM)
• social:
• sharing of files, of displays, in paper, across great
distances, work individually, privacy for clients
• organisational:
• hierarchy, IT department’s attitude and remit, user
support, communications structure and infrastructure,
availability of training
AN EXTREME EXAMPLE
DIFFERENT KINDS OF REQUIREMENTS
•
Users:
Who are they?
— Characteristics: ability, background, attitude to
computers
— Prior Experience: novice, expert, casual, frequent
 Novice: step-by-step (prompted), constrained, clear information
 Expert: flexibility, access/power
 Frequent: short cuts
 Casual/infrequent: clear instructions, e.g. menu paths
KINDS OF REQUIREMENTS
What factors (environmental, user, usability)
would affect the following systems?
• Elevator in McBryde
• Self-service filling and payment system for a gas station
• On-board ship data analysis system for geologists searching for oil
• Online community for local musicians
PERSONAS

Capture user characteristics

Not real people, but synthesised from real user
characteristics

Should not be idealised

Bring them to life with a name, characteristics, goals,
personal background

Develop multiple personas
DATA GATHERING FOR REQUIREMENTS
Interviews:
— Props, e.g. sample scenarios of use,
prototypes, can be used in interviews
— Good for exploring issues
— But are time consuming and may be
infeasible to visit everyone
Focus groups:
— Group interviews
— Good at gaining a consensus view and/or
highlighting areas of conflict
— But can be dominated by individuals
DATA GATHERING FOR REQUIREMENTS
Questionnaires:
— Often used in conjunction with other techniques
— Can give quantitative or qualitative data
— Good for answering specific questions from
a large, dispersed group of people
Researching similar products:
— Good for prompting requirements
DATA GATHERING FOR REQUIREMENTS
Direct observation:
— e.g. work study / time study
Indirect observation:
Studying documentation:
— Procedures and rules are often written in
manuals
— Legislation, policies, guidelines
Contextual Inquiry
• An approach where user is expert, designer is apprentice
• A form of interview, but
— at users’ workplace (workstation)
— extended: 2 to 3 hours long
• Four main principles:
— Context: see workplace & what happens
— Partnership: user and developer collaborate
— Interpretation: observations interpreted by user and
developer together
— Focus: project focus to understand what to look for
PROBLEMS WITH DATA GATHERING (1)



Identifying and involving stakeholders:
users, managers, developers, customer reps?, union reps?,
shareholders?
Involving stakeholders: workshops, interviews, workplace studies, coopt stakeholders onto the development team
‘Real’ users, not managers:
traditionally a problem in software engineering, but better now
PROBLEMS WITH DATA GATHERING (2)




Requirements management: version control, ownership
Communication between parties:
— within development team
— with customer/user
— between users… different parts of an organisation use
different terminology
Domain knowledge distributed and implicit:
— difficult to dig up and understand
— knowledge articulation: how do you walk?
Availability of key people
PROBLEMS WITH DATA GATHERING (3)
• Political problems within the organisation
• Dominance of certain stakeholders
• Economic and business environment changes
• Balancing functional and usability demands
SOME BASIC GUIDELINES
• Focus on identifying the stakeholders’ needs
• Involve all the stakeholder groups
• Involve more than one representative from
each stakeholder group
• Use a combination of data gathering
techniques
SOME BASIC GUIDELINES
• Support the process with props such as
prototypes and task descriptions
• Run a pilot session
• You will need to compromise on the data
you collect and the analysis to be done,
but before you can make sensible
compromises, you need to know what
you’d really like
• Consider carefully how to record the data
Group 1
Group 2
Group 3
Erickson,
Benjamin
Weisberg,
Alexander
DeForge, Jason
Mey, Henjo
Lilly, Kyle
Everett, Mark
Lin, Yu-Hsun
Group 4
Group 5
Group 6
Bourne, Joseph Zimmer, Andrew
Harris, Morgan
Braley, Colin
Probus, Stephen
DelValle, Eric
Lindner, William
Dove, Andrew
Cammarata,
Matthew
Cline, James
Chelko, Jared
Scott, Benjamin
McFarland,
Daniel
Eltahir, Idris
Willis, Brad
Cox, William

GROUPS:
 Project
Step 1
 Project Ideas
QUIZ

Name the types of requirements.

Name 3 type of task descriptions

Why does all software suck?
DATA INTERPRETATION AND ANALYSIS
• Start soon after data gathering session
• Initial interpretation before deeper analysis
• Different approaches emphasize different
elements e.g. class diagrams for objectoriented systems, entity-relationship
diagrams for data intensive systems
TASK DESCRIPTIONS
• Scenarios
― an informal narrative story, simple, ‘natural’,
personal, not generalisable
• Use cases
— assume interaction with a system
— assume detailed understanding of the interaction
• Essential use cases
— abstract away from the details (e.g. choice/option)
— does not involve the same assumptions as use
cases
SCENARIO FOR HOLIDAY PLANNER
“The Thomson family enjoy outdoor activity holidays and want to try
their hand at sailing this year. There are four members of the family:
Sky who is 10 years old, Eamonn who is 15 years old, Claire who is
35, and Will who is 40. While out on a shopping trip they call by at
the travel agents in their local town to start exploring the possibilities
... The travel organizer is located in a quiet corner of the agents’
office, where there are comfortable seats and play things for young
children. They all gather around the organizer and enter their initial
set of requirements—a sailing holiday for four novices. The standalone console is designed so that all members of the family can
interact easily and comfortably with it. The system’s initial
suggestion is that they should consider a flotilla holiday, where
several novice crews go sailing together and provide mutual support
for first-time sailors…”
USE CASE FOR HOLIDAY PLANNER
1. The system displays options for investigating visa and vaccination
requirements.
2. The user chooses the option to find out about visa requirements.
3. The system prompts user for the name of the destination country.
4. The user enters the country’s name.
5. The system checks that the country is valid.
6. The system prompts the user for her nationality.
7. The user enters her nationality.
8. The system checks the visa requirements of the entered country for
a passport holder of her nationality.
9. The system displays the visa requirements.
10. The system displays the option to print out the visa requirements.
11. The user chooses to print the requirements.
ALTERNATIVE COURSES FOR HOLIDAY
PLANNER
Some alternative courses:
6. If the country name is invalid:
6.1 The system displays an error message.
6.2 The system returns to step 3.
8. If the nationality is invalid:
8.1 The system displays an error message.
8.2 The system returns to step 6.
9. If no information about visa requirements is found:
9.1 The system displays a suitable message.
9.2 The system returns to step 1.
EXAMPLE USE CASE DIAGRAM FOR HOLIDAY PLANNER
Identify potential
Holiday options
Update holiday
details
Retrieve visa
requirements
Retrieve vaccination
requirements
Travel agent
Holidaymaker
EXAMPLE ESSENTIAL USE CASE FOR HOLIDAY PLANNER
retrieveVisa
USER INTENTION
find visa requirements
supply required information
obtain copy of visa info
choose suitable format
SYSTEM RESPONSIBILITY
request destination and nationality
obtain appropriate visa info
offer info in different formats
provide info in chosen format
TASK ANALYSIS

Task descriptions are often used to envision new systems or
devices

Task analysis is used mainly to investigate an existing
situation

It is important not to focus on superficial activities
What are people trying to achieve?
Why are they trying to achieve it?
How are they going about it?

Many techniques, the most popular is Hierarchical Task
Analysis (HTA)
HIERARCHICAL TASK ANALYSIS

Involves breaking a task down into subtasks, then sub-subtasks and so on. These are grouped as plans which specify
how the tasks might be performed in practice

HTA focuses on physical and observable actions, and
includes looking at actions not related to software or an
interaction device

Start with a user goal which is examined and the main tasks
for achieving it are identified

Tasks are sub-divided into sub-tasks
EXAMPLE HIERARCHICAL TASK ANALYSIS
0.
In order to borrow a book from the library
1.
go to the library
2.
find the required book
2.1 access library catalogue
2.2 access the search screen
2.3 enter search criteria
2.4 identify required book
2.5 note location
3.
go to correct shelf and retrieve book
4.
take book to checkout counter
EXAMPLE HIERARCHICAL TASK ANALYSIS
(PLANS)
plan 0:
do 1-3-4.
If book isn’t on the shelf expected, do 2-3-4.
plan 2:
do 2.1-2.4-2.5.
If book not identified do 2.2-2.3-2.4.
EXAMPLE HIERARCHICAL TASK
ANALYSIS (GRAPHICAL)
Borrow a
book from the
library
0
plan 0:
do 1-3-4.
If book isn’t on the shelf expected, do 2-3-4.
go to the
library
1
find required
book
2
retrieve book
from shelf
3
take book to
counter
4
plan 2:
do 2.1-2.4-2.5.
If book not identified from information available, do 2.2-2.3-2.4-2.5
access
catalog
2.1
access
search
screen 2.2
enter
search
criteria 2.3
identify
required
2.4
book
note
location
2.5
SUMMARY
•
Getting requirements right is crucial
•
There are different kinds of requirement, each is
significant for interaction design
•
The most commonly-used techniques for data gathering
are: questionnaires, interviews, focus groups, direct
observation, studying documentation and researching
similar products
•
Scenarios, use cases and essential use cases can be
used to articulate existing and envisioned work practices.
•
Task analysis techniques such as HTA help to investigate
existing systems and practices